1. Technical Field
The present invention relates to a method of calculating a correction value and a method of discharging liquid.
2. Related Art
As one type of liquid discharging devices, there are ink jet printers that perform a printing operation by discharging ink on various media such as a sheet, a cloth, or a film from a nozzle. Recently, as one type of the ink jet printers, line head printers having a nozzle row of a length corresponding to the sheet width in a predetermined direction intersecting a transport direction of a medium have been developed.
Non-uniformity of density may occur due to a problem such as precision of nozzle processing, landing of ink droplets in an inappropriate position on the medium, or a difference of ink discharging amounts. Thus, a correction value is calculated such that an image piece that is visually recognized thin is printed thick and an image piece that is visually recognized thick is printed thin. Accordingly, an actual test pattern is printed by the printer. Then, a method in which the test pattern is read out by the scanner, and a correction value is calculated based on the read-out result has been proposed (for example, JP-A-2006-305952).
In a printer having a long head, a long test pattern in a predetermined direction is printed. However, there is limit on the range in which the test pattern can be read out by the scanner. Accordingly, a test pattern that is printed by the printer having a long head cannot be read out by the scanner, and therefore, a correction value cannot be calculated.
Thus, a method of calculating a correction value of the printer having the long head is needed.